i got an old IBM T41-Notebook and the noise off the fan is pretty annoying.
So i adpated that HOWTO from the thinkwiki (thinkwiki.org/wiki/How_to_control_fan_speed) to BackTrack3.

First you need to load the necessary kernel-module via

Code:

modprobe -v ibm-acpi experimental=1

After that has been done you should be able to read many informations of your machine out of /proc/acpi/ibm.
For instance temperatures (check thinkwiki to be sure which temp represents which sensor in your machine)

where the "2" was just an example for the fanspeedlevel. Watch out that "0" stops the fan completely!! That could be dangerous so watch your temps!

Code:

watch cat /proc/acpi/ibm/thermal

. If you dont wanna take any risk switch to the "auto" level which is probably pretty noisy.

There is also a very nice script that controls your fans automaticially, you may get it from: thinkwiki.org/index.php?title=Code/tp-fancontrol&action=raw&ctype=application/octet-stream just save it as .sh and chmod +x it to make it executable. Run it with ./ and everything works fine as long as you have loaded the ibm-acpi kernelmodule and running that stuff as root which is the default case unter backtrack3